Prostate Disease in Dogs

Prostate problems occur typically in older male dogs, especially intact (not neutered) males. Prostatitis describes inflammation of the gland, of which there are three categories: benign prostate hyperplasia (BPH), bacterial prostatitis, and prostatic neoplasia (cancer). Because the prostate surrounds the urethra, the tube that carries urine outside of the body, symptoms usually include urinary tract disorders.

A dog with prostatitis may present with lethargy, a strained gait and arched back, blood in the urine, or a purulent discharge (pus). He may be constipated and pass narrow diameter stools because of prostate enlargement. Prostatitis can be chronic with subtle symptoms as well.

The veterinarian will confirm prostatitis by rectal palpation of the gland to feel for enlargement, asymmetry, obvious masses, or fluctuant areas (soft spots). Lab work should include a complete blood count, chemistry panel, and urinalysis. These tests are used to categorize the prostate disease and rule out other systemic illness. An x-ray or ultrasound of the urinary tract will help to visualize the degree of enlargement or masses associated with the gland. Urine sediment analysis may reveal increased numbers of red and white blood cells which are not found in healthy urine. Bacteria may be seen which would warrant a culture and susceptibility test. This would be indicative of primary or secondary bacterial prostatitis.

The most common type of prostate disease in dogs and man is benign prostate hyperplasia. This simply means non-cancerous enlargement. It is associated with changes in the male sex hormone levels as the dog ages. Neutering can reduce the chance of BPH significantly. Studies indicate that neutering at less than one year can all but eliminate BPH in male dogs. The treatment for BPH is in fact, neutering. This type of prostatitis is almost always chronic and recurrent if the dog remains intact. Secondary bacterial infection is common with BPH because the normal antibacterial secretions from the prostate are diminished and red blood cells provide food for the organisms.

Acute or chronic bacterial prostatitis occurs in both intact and neutered male dogs. Usually the bacteria have ascended the urethra from the outside world. Broad spectrum urinary tract specific antibiotics are prescribed while the results of a culture and susceptibility test are pending. Bladder stones and other urinary tract disease may be associated with bacterial prostatitis.

Prostatic neoplasia is the rarest of the prostate diseases comprising about 5% of all cases. Neoplasia means new growth and refers to cancer. In humans, there is an antibody specific to prostate cancer that can be measured in the blood. Unfortunately, there is no reliable blood test for dogs at this time. The prognosis for prostate cancer in dogs is poor. The cancer is aggressive and has likely metastasized to other organs by the time of diagnosis. A needle biopsy and histopathology report can help to diagnose prostatic neoplasia. Poor response to other treatments and progression of disease usually verifies cancer as the diagnosis.